Mancini made nine changes to his starting line-up against the European champions as he continued his search for the right players to help him rebuild Italy following their failure to qualify for this year’s World Cup.

But the four-times world champions went down with barely a whimper to a Portugal side who allowed themselves the luxury of resting Cristiano Ronaldo and Italy’s performance suggested Mancini has a long road ahead.

“Italy always going downwards,” said the Gazzetta dello Sport, summing up the general sentiment which followed the team’s fourth competitive match without a win.

The only players to leave Lisbon with any praise were goalkeeper Gianluigi Donnarumma, who at 19 appears to be the natural heir to Gianluigi Buffon, his Milan team mate Alessio Romanogli in defence and forward Simone Zaza.

Italy’s midfield was disjointed and even Federico Chiesa, who lit up their 1-1 draw with Poland on Friday after coming on as a substitute, failed to provide the same spark.

Mancini fielded Bryan Cristante and Jorginho in central midfield with Chiesa and Giacomo Bonaventura on the flanks in a formation which occasionally resembled the much-maligned 4-2-4 used by his hapless predecessor Gian Piero Ventura.

Zaza was partnered by Ciro Immobile in a two-man strikeforce but, not for the first time, Immobile, a prolific scorer for Lazio, was a let-down playing for his country.

With Italy short of world-class players, Mancini insisted the only way forward was to test less experienced players even when they lack playing time at club level.

These included Mattia Caldara who has yet to make his debut for AC Milan following his move from Juventus.

Mancini has complained that Italian players are being squeezed out by foreigners at Serie clubs.

“It is true that we have many young players and we are in an experimental phase, however we must continue on this path and pick ourselves up as soon as possible,” he said.

“If a young player doesn’t play at a high level then it’s clear that they’ll struggle in the first few games, however, we knew this before.”

If Italy finish bottom of the three team group, they will be relegated to League B of UEFA’s new competition — a price Mancini said they would have to risk paying as he continued to experiment.

“We do not like losing, it’s bad, but it’s also true that we have to take risks and get experience in these games,” said Mancini, who emphasised that the priority was to qualify for Euro 2020.

“We knew there were problems in this squad, because otherwise Italy would have qualified for the 2018 World Cup.”

The European Championship qualifying competition, which is separate from the Nations League, starts in March.